| Abbreviation | Definition |
|---|---|
| CLOP | Characterization Laboratory for Organic Photovoltaics |
| CLP | Contract Laboratory Program |
| CLR | Cell Loss Ratio |
| CLRC | Central Laboratory of the Research Councils |
| CLRP | Carleton Laboratory for Radiotherapy Physics |
| CLRP | Comprehensive Laboratory Response Plan |
| CLRT | Clandestine Laboratory Response Team |
| CLS | Clinical Laboratory Sciences |
| CLS | Colorado Laboratory Services |
| CLSA | Canadian Laboratory Suppliers Association |
| CLSC | Clinical Laboratory Science Courses |
| CLSI | Clinical and Laboratory Standards Institute |
| CLSS | Clandestine Laboratory Seizure System |
| CLT | Certified Laboratory Technician |
| CLT | Clinical Laboratory Technician |
| CLTI | Clinical Laboratory for Therapeutic Individualization |
| CLTR | Clinical laboratory test reference |
| CMC | Chemical Manufacturing Control |
| CMC | Controlled Microbial Composting |
| CMC | Critical Micellar Concentration |